Activated-sludge treatment.



onoon, or FORT-WORTH, mixes,

ASSIGNDRTO ABMQUB AND COMPANY, OF

CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AOTIVATED-SLUDGE TREATMILNT.

K Drawing. a

To all whom'it may concern: 7 I

Beit known that I, WILIJIAM C..MOOR, a citize'n of the United States,"residing at Fort W'Orth, in the county of Tarmntand State of Texas, haveinvented eel-tam new and useful Improvements in Activated-- SludgeTreatment, of which thexfollo wm g is a specification.

v The activated sludge method of sewage disposal, though ofcomparatively modern origin-Land infitsinfancy, is one high 1S wellknown and constitutes a field ofiactlvlty for sanitary engineers intheeffort tosurmount pljejsent difiiculties in its application toe widerrange of usefulness and in experimentation :to. increase its efficiencyand economical availability.

Briefly. and generally sta ted, the activated treatment of sewageconslsts 1n con- 20 ductingithe r aw swageinto and throughaefetin'gjtagnks provided with means for the introduction. of air underpressure totthe 'botto'tnjof tlieitit nk, whereby the air is causedtobflbble up -throughthe liquid sewage. The' pess'egeof the air throughthe sewage dmtelopSdn'time microscopic aerobic organ- .isniswhioh in thecourse of thein growth or means of conditions ,.p.rov1ded by their.gmwth, oxidize the eollodii'l and soluble solids init'he sewage ea'usi1.1g them tos'eperate "outa'sflocculent particles. The treatedsewatgtheproper stage is run intoia settling yyminutesto-iene houryandithe tle'to; the bottom. as. a. fioceulent ted-sludge, I

liquid: content of ltf e-ctl-y clear, wh v redils eyaih'ble aferige,u-pe1:centuge 10f being; practically. dors. ;w1 s ajnd in or 1entt,n;f .:the'irew. s -vanta' 80118; toinoculate ctioxiQto: the;aerati; te sludge fnomisewagel 99pm cent.,.but prolonged; settling is ininstallation required for the hepe" 1 t y s; allowed"to-nemaiuquies'eent 1, i une" :ttalize the'slud'gey thorough. .gaseeus-Iii means ofgzir, all oug ctegeous'ly used,

" hy. e P etzels '1 f s immnon of Letters 2mm. t nt a 29, 1913, IApplication filed m a, 1917. sem No. 179,499

reduced in point of time from several days to a :few hours.The'de-hydrati0n'of the sludge resulting from this activated sludgemethod of sewage disposal, is the most-discouraging problem encountered'in the practical employment of that method of treatihgindustrialsewage.

Activated sludge, by'reeson of its physical and chemical cl u tra;( ;te1-i'stics, is a most valuable. fertilizer, but the economical utilization,of. the sludge has not thus fanbeen peslsjhl vging to the fact that asfound in he ettl H g flank the sludge isflightf and flaky, has aspecific gravity of at nt- 1.02, and-When siphoned oil-averages 799.5%of water. Bysubje'eting the withdrawn sludge to .a further settling forfrom four tO-six hours, the Water content can be reduced to- I hibitedowing-to the fact that-(the 'sl'ud-gebecomes septic 1f maintained toolonguwlthout air," 'the' cutting off of the air s uliply; permitting therenewed growth, of the anaerobic organisms and 'thein. domination of thegradually weakening. aerobic: organisms. I

For the further dehydrating 10f the sludge, extensive experiments, havebeen needeulong tthe lines of? centrifuging, filter pressingfla'nddryinggbut nonebf thesehave preven satistaetor'y; being uneeonolnical byreason of thetime required and high cost of y By:- thepresentinventions; ev'tictivatedsludge, .whmh isdiff -re 0 ordinary sewg ludge b reasonqoft e fectthat 1t he's as.90

" teted ids end 11158 sulfuric acid,

"d" stunt em m 'fi 3 51 7 1 ofiagul the slud e and produ ing -t;geses; yearben ioxid, whiCh-fqlgussflthe 'lludg ite-ffi rst rise to the u c ndthen :Sefi thenebypermittinf th easy withdraws-i1- of therembbihinfl'likpi whereby the totel' volume of sludge: to be' yin l dfi' slt rees d. by we 995139: 9

and the-mois'ure content of the sludge reduced to suchan extent that itcan be readily removed as fa rubbery mass, drained and dried.

The treatriient of the sludge by the acid as above described, also fixesany volatile or easily decolinposed nitrogen compounds that areotherwise certain to be driven off duringthe drying process. This actionof the acid in fixing the ammonia content of the sludge is important, inits original condititon much of the ammonia is volatile, and the sludgebe dried without applying the acid treatment this volatile ammoniaishkely to be lost, thus depriving the fertilizer cl its most valuableconstituent.

it will thus be seen that I have, by the present process, achieved aderided advance in the activated sludge methodcf sewage disposal, inthat the sludge is made madily available as u fertili' the return fromwhich is more than icient to rm-er the entire cost of the ewagetreatment, whereas heretofore the sludge has not been ecnoznieallyavailable for this purpose :by reason of the expense and difiieulty oftie-hydrating the same.

I claim 1. The method of dehydrating activated sludge which consists inheating the same above thirty degrees Centigrade, then subjecting thesame to the action of an acid whereby coagulation takes Place, and thenseparatin the cceguial'ied sludge fron'i the liquid.

2. The method of r le-hydrating activated sludge which consists insubjecting the same to the sin'iultaneoue action of an acid and toagitation by means of a introduced there to whereby eoagulatiten takesplace, then separating the coagulated sludge from the liquid, anddrying.

3. The method of die-hydrating activated sludge which consists insubjecting the same to the simultaneous action of an acid and toagitation by means of air whereby eonglllzttion takes place, thenseparating the eougulated sludge from the liquid, and drying.

4;. The method of dehydrating activated vsludge which consists insubjectin the same to the action of sulfuric acid wfiereby coagulationtakes place accom anied by the generation of gases and t c coagulatedslmige is caused to float, and then separat ing the ceugulated floatingsludge from the liquid.

5. The method of de-hydrating activated sludg which consists in heatingthe ame above 30 (3., then subjecting the same to the action of sulfuricacid whereby cc- :igulation takes place accompanied by the generation oftherein and the coagulated sludge is caused to float, and thenseparating the-coagulated floating sludge from the liquid, and drying.

6. The method of de-hydratingactivated sludge which consists in heatingthe same above 30 (1., then subjecting the same to the action ofsulfuric acid and agitation by means of airv whereby coagulation takesplace accompanied by the generation of gas therein and the coagulatedsludge is caused to float, and then separating the coagulated floatingsludge from the liquid, and drying.

WILLIAM C. MOOB.

Witnesses A. B. STRATTON,

G. McDoNALn.

